High magnetic field electromagnets have become important in various types of equipment over recent years. One important type of such equipment is medical imaging equipment, such as the type commonly referred to as magnetic resonance imaging (MRI) equipment
Contrast-Enhanced Breast MRI (CE-BMRI) is a sensitive screening method for the detection of breast cancer. Studies of CE-BMRI among women in high-risk groups report sensitivities in the range 71-100%, versus mammography sensitivities in the range 20-50%. Breast MRI is more sensitive but less specific than mammography for women with dense breasts, but it is much more expensive and thus is presently not utilized for screening.
CE-BMRI is conventionally performed in a 1.5 T whole-body MRI system, utilizing a large cylindrical solenoid to a high-quality imaging field. Such systems are expensive (˜$1.5 million for the system, $0.5 million for the room within the 5 G line). Additionally, whole-body MRI systems restrict access for interventional procedures such as needle biopsy and lumpectomy.
Present-day open MRI systems are based on a Helmholtz-type coil configuration, for example the 1T Panorama scanner from Phillips and the resistive passively shielded 0.6T from Fonar Corporation. However, no existing unit can provide the 1.5 T field required for CE-BMRI sequences. Thus, there is a need for MRI systems that can provide the appropriate signal and thereby field strength required for applications such as CE-BMRI, while at the same time providing access to the patient during the procedure.